1. Field of the Invention
The present invention relates to a recording apparatus, and more particularly, to a recording apparatus that transfers images to a recording sheet using a transfer film.
2. Description of the Related Art
In recent years, color recording is performed based on an electrophotographic system. In this type of color recording, a transfer film is used to superimpose images in 4 colors. That is, images in 4 colors are transferred to a same position to form a color image on a transfer film. This color image is further transferred to a recording sheet. When the transfer of the color image to the recording sheet is completed, used toner remaining on the transfer film is cleaned.
Conventionally, the cleaned used toner is collected in a used toner box. When the used toner box is filled with used toner, this used toner box is replaced. This used toner box is normally provided in a location different from the location where the transfer film is placed. The transfer film cleaning mechanism and the used toner box are connected via a pipe that carries used toner.
However, when the used toner box is replaced, such a conventional configuration requires the used toner box to be removed from the pipe. In this case, there is a problem that used toner leaks from the pipe, causing the recording apparatus interior to get soiled. Moreover, providing an additional mechanism that prevents soiling when the used toner box is removed from the pipe will increase the size of the recording apparatus due to the additional mechanism as well as costs due to increased number of parts.
In order to solve such a problem, a unit that combines the used toner box and transfer film (hereinafter referred to as "transfer unit") is provided in which the used toner box is housed in a space inside the transfer film circulation path. It is also possible to replace the entire transfer unit when the used toner box is filled with used toner.
According to such a recording apparatus, the entire transfer unit containing the used toner box is replaced, and therefore it is not necessary to remove the used toner box from the pipe. This prevents used toner from leaking, which will also prevent the recording apparatus interior, etc. from getting soiled. Housing the used toner box inside the transfer unit also reduces the size of the recording apparatus.
With such a recording apparatus, however, the transfer unit needs to be replaced not only when the used toner box in the transfer unit is filled with used toner, but also when the number of times the transfer film is developed reaches the maximum number of times the transfer film can be developed. Thus, since the number of times the transfer film is developed can reach the maximum number of times the transfer film can be developed before the used toner box in the transfer unit is filled with used toner, it is necessary to precisely control the development count of the transfer film.
Thus, every time the transfer unit is replaced it is detected whether the replaced transfer unit is an unused unit or not. If the transfer unit is an unused unit, it is necessary to reset the development count of the transfer film in this transfer unit and restart counting. Then, when this count reaches a predetermined value, the entire transfer unit is replaced. Therefore, with this recording apparatus it is necessary to detect whether the replaced transfer unit is an unused unit or not.
As a method for detecting whether the replaced transfer unit is an unused unit or not, it is possible to attach a fuse to the transfer unit which is blown out when the transfer unit is mounted and detect whether the transfer unit is an unused unit or not by the presence or absence of the fuse. However, such a detection method requires a circuit for burning out the fuse and a circuit for detecting the presence or absence of the fuse. This will increase the number of parts in the recording apparatus, causing a problem of increasing costs as well. Moreover, the necessity for providing an additional electric circuit will make the configuration of the recording apparatus complicated.